This research is aimed at elucidating each of the components and reactions involved in the physiologic permeability effects of antidiuretic hormone (ADH) and parathyroid hormone (PTH) in the kidney. The effects of these hormones on phosphorylation of proteins in the cytosolic and plasma subcellular fractions are to be delineated. Tissue slice and perfused kidney systems will be utilized. Experiments on the toad bladder system are aimed at elucidating effects of ADH on luminal membrane proteins. Chemical modification, radiolabeling (125I) and fluorescence probe approaches will be used in these studies. The response of brush border plasma membranes isolated from an animal model for X-linked hypophosphatemia to cAMP are also being examined.